This invention pertains to the field of scanning probe microscopy and to micro-electro-mechanical devices with nanometer probe tips having integrated sensor elements.
Scanning probe microscopy (SPM) is used to provide information about the surface structure and physical properties of a measurement sample with nanometer or angstrom scale resolution. SPM measurements are typically performed using a physical probe, which for many applications may be a sharp needle-like tip located at the distal end of a micro-machined cantilever. The tip is brought in contact with or in close proximity to a sample and interacts with the sample at one or more points in a controllable manner. In some cases, a scan is carried out in a raster pattern using a piezoelectric-controlled tube to which the probe is attached or by moving the sample using a piezoelectric-controlled stage, and the purpose of the scan may be to produce a nanometer scale map of the surface topography. In this mode, the tip interacts with the sample surface resulting in a detectable signal which, along with information about the position of the tip relative to the sample, is used by a graphical computer to construct a two dimensional map of a desired physical property and/or a three dimensional image of the surface topography.
Tip-sample interactions may include any number of physical interactions: mechanical, electrostatic, magnetic, thermal, chemical, or optical. Atomic force microscopy (AFM), for example, uses the mechanical force between a probe tip and a sample surface to map topography. AFM probes are relatively simple structures typically consisting of silicon or silicon nitride tips with nanometer radius of curvature.
Measuring physical properties besides topography may use probes with sensing structures at or near the tip. Such probes can be used to measure magnetic domains, electrochemical signals or thermal properties. To measure temperature, for example, a thermocouple, thermistor, or Schottky diode sensor can be constructed near the probe tip.